Method of making playing balls



4Patentecl May 14, 1929.

UNITED STATES WILI'BED L. CEILDS, OI' EVASTON, ILLINOIS.

lumaon or MAKING name nuts? Application led April 11,

This invention relates to improvements in playing balls and process of making the same, and more especially to such balls inflated with air, or other` gases, for example, basket balls, footballs, soccer balls, volley balls, waterpolo balls, and the like.

One of the objections to balls of this type as heretofore made, is that they soon stretch and losetheir shape under normal playing conditions. One of the objects of my invention is to produce a ball that will not do this.

My invention is applicable to a ball of the type referred to which is usually made of an outer supporting cover and an inner gas-tight bladder. For example, the outer cover may be leather and the bladder rubber. The cover frequently is provided with a lining, such as canvas, which may be sewed to the cover, or otherwise attached. The bladder may be of any type, and may have the well known rubber nipple, which may be formed on the inside and provided with an automatic valve.

In the practice of my invention, I may use certain apparatus shown in the accompanying' drawings, in which- Fig. 1 isa vertical Sectional view of a mold showing a ball inside, andv Figs. 2 and 3 are plan views of the two portions of the mold showing the same separated. 4

For the purpose of illustrating my invention, I have here shown the same as practiced in the making of a spherical ball, as for example a basket-ball, but it is to be understood that it is equally well applicable in connection with the making of balls of other sizes and shapes.

As shown in the drawings, 10 and 10 indicate the two halves of a mold provided with the interior spherical cavity 11 of the size and. shape of a completed ball. Suitable clamping means, as indicated by 12, are provided for holding the parts of the mold together. 113 indicates a hole in one of the mold parts to accommodate the nipple of the bladder or ,the inflating tube.

The cover for my improved ball may be cut in accordance with any pattern or design, but it must be cut smaller than the size of the completed ball. For example, if a spherical leather basket-ball of 30 inches circumference is desired, I may cut the original cover so that, Without stretching, it Will have a circumference of substantially 28.6 inches.

The cavity 11 in the mold is given the circumference of the completed ball, in this case 30 inches. How much undersized the cover 1928. Serial ll'o. 268,238.

is to be cut depends somewhat upon the kind of material used, its strength and thickness, stretchablty, and the like. The cover ma be lned or not. I have found that if lining s used, the initial stretching of the ball may v have to be relatively slower, possibly in two or more steps, the lining.

In making the cover, I preferably use materal of suflicient thickness and weight so that the completed ball will be of the desred specifications. For example, in making a 30 nch basket-ball, I use leather thick and heavy enough for the original undersized cover so that when it is stretched to the final 30 nch size, the completed ball will then have the desired weight and thickness. a A fter completing the undersized cover, as indicated by 14, I place it in the mold 10 witha suitable bladder and' stretch it under excessve pressure by gas or liquid until it conforms to the mold. Orginarily, the mold s enough larger so that when the ball is thus stretched it will not stretch substantially any more thereafter under normal pressure and normal playing conditions. In other words,

in order to prevent tearing of .I aim to give the ball anv initial stretching that will stretch the 'same 'substantially to its stretchable limit.

By stretchable limit,,, I mean the limit to-which it would stretch under normal pressure and normal playing conditions. By thus giving it' this initial stretching, at an excessive pressure in a relatively short space of time in the process of manufacture, there is practically no more stretching thereafter in the ordinary use with the normal pressure. In the case of a leather basket-ball designed for a normal pressure of about 13 pounds, this initial stretching may be accomplished by imposing a pressure of about 25 pounds for about 12 hours and then increasing the pressure to about 80 pounds, leaving the ball in the mold for about 12 hours longer. The exact time and pressure required for this initial stretching depends upon the material used, size and shape of the ball, and whether or not lining is used. The best results can be obtained by experimentation.

VVhile I have shown and described certain embodiments of my invention, it is to be understood that it is capable of many modifications. Changes, therefore, in the construction and arrangement may be made without departing from the spirit and scope of the invention as disclosed in the appended claims, in which it is my intention to claim all novelty inherent in my invention as broadly as possible in view of theprior art.

What I claim as new, and desire to secure by Letters Patent, is:

1. The process of making a playing ball consisting of first making an undersized ball, and then stretching the same to substantially its stretchable limit, under pressure exceeding that for which the ball is designed for normal pla 2. The process of making a playing ball consisting of first making an undersized ball, and then stretching the same in a'mold 15 to substantially 'its stretchable limit, under ressure exceeding that for which the ball i sdesigned for normal la v 3. The method of making a playing ball consisting of first making an undersized 20 ball, and then stretching the same in a mold to substantially its normal size and shape under pressure exceeding that for which the ball is designed for normal play.

In witness whereof, I have hereunto set 25 my hand this 7th day of April, 1928.

WILFRED L cHILDs. 

